Friends are going to play console. They have two joysticks and only one charger for them. Initially first joystick is charged at a1 percent and second one is charged at a2 percent. You can connect charger to a joystick only at the beginning of each minute. In one minute joystick either discharges by 2 percent (if not connected to a charger) or charges by 1 percent (if connected to a charger).

Game continues while both joysticks have a positive charge. Hence, if at the beginning of minute some joystick is charged by 1 percent, it has to be connected to a charger, otherwise the game stops. If some joystick completely discharges (its charge turns to 0), the game also stops.

Determine the maximum number of minutes that game can last. It is prohibited to pause the game, i. e. at each moment both joysticks should be enabled. It is allowed for joystick to be charged by more than 100 percent.

The first line of the input contains two positive integers a1 and a2 (1 ≤ a1, a2 ≤ 100), the initial charge level of first and second joystick respectively.

Output the only integer, the maximum number of minutes that the game can last. Game continues until some joystick is discharged.

In the first sample game lasts for 6 minute by using the following algorithm:

• at the beginning of the first minute connect first joystick to the charger, by the end of this minute first joystick is at 4%, second is at 3%;
• continue the game without changing charger, by the end of the second minute the first joystick is at 5%, second is at 1%;
• at the beginning of the third minute connect second joystick to the charger, after this minute the first joystick is at 3%, the second one is at 2%;
• continue the game without changing charger, by the end of the fourth minute first joystick is at 1%, second one is at 3%;
• at the beginning of the fifth minute connect first joystick to the charger, after this minute the first joystick is at 2%, the second one is at 1%;
• at the beginning of the sixth minute connect second joystick to the charger, after this minute the first joystick is at 0%, the second one is at 2%.

After that the first joystick is completely discharged and the game is stopped.

第一cf 出三题 进入rank1000

题意： 两个电池 初始电量为a1 a2 不充电的话每分钟减少2格电 充电的话每分钟增加1格电 当前只有一根充电线 也就是只能给其中一个电池充电

当其中任意一个电池电量小于等于0时结束 或者都为1时结束  问 这个过程最多能持续多少分钟

题解： 可以判断 若要这个过程持续 必须使电量大的电池的电量大于等于2 知道这个就很好写了

 #include<bits/stdc++.h>

 #include<iostream>

 #include<cstdio>

 #define ll __int64

 using namespace std;

 int a,b;

 int main()

 {

      scanf("%d %d",&a,&b);

      int maxn=,jishu=,t;

      maxn=max(a,b);

      while(maxn>=)

      {

          if(a>b)

          {

              t=a;

              a=b;

              b=t;

          }

          if(a<=)

             break;

          a=a+;

          b=b-;

          maxn=max(a,b);

          jishu++;

      }

      printf("%d\n",jishu);

     return ;

 }