You're given strings J representing the types of stones that are jewels, and S representing the stones you have.  Each character in S is a type of stone you have.  You want to know how many of the stones you have are also jewels.

The letters in J are guaranteed distinct, and all characters in J and S are letters. Letters are case sensitive, so "a" is considered a different type of stone from "A".

Example 1:

Input: J = "aA", S = "aAAbbbb"

Output: 3

Example 2:

Input: J = "z", S = "ZZ"

Output: 0

Note:

• S and J will consist of letters and have length at most 50.
• The characters in J are distinct.

class Solution {

public:

    int numJewelsInStones(string J, string S) {

        int res=;

              map<char,int> m;

              for(auto a:J){

                  m[a]++;

              }

              for(auto a:S){

                  if(m[a]!=) res++;

              }

              return res;

    }

};