#include<cstdio>

 #include<cstring>

 #include<algorithm>

 #define rd read()

 #define lson nd << 1

 #define rson nd << 1 | 1

 using namespace std;

 const int N = 1e4;

 int dep[N], top[N], f[N], son[N], size[N], id[N];

 int q, n, head[N], tot, cnt, A[N], a[N];

 int sum[N << ];

 struct edge {

     int nxt, to, val;

 }e[N << ];

 int read() {

     int X = , p = ; char c = getchar();

     for(; c > '' || c < ''; c = getchar()) if(c == '-') p = -;

     for(; c >= '' && c <= ''; c = getchar()) X = X *  + c - '';

     return X * p;

 }

 void added(int u, int v, int val) {

     e[++tot].to = v;

     e[tot].nxt = head[u];

     e[tot].val = val;

     head[u] = tot;

 }

 void add(int u, int v, int val) {

     added(u, v, val);

     added(v, u, val);

 }

 void dfs1(int u) {

     size[u] = ;

     for(int i = head[u]; i; i = e[i].nxt) {

         int nt = e[i].to;

         if(nt == f[u]) continue;

         f[nt] = u; dep[nt] = dep[u] + ;

         a[nt] = e[i].val;

         dfs1(nt);

         size[u] += size[nt];

         if(size[nt] > size[son[u]]) son[u] = nt;

     }

 }

 void dfs2(int u) {

     id[u] = ++cnt;

     A[cnt] = a[u];

     if(!son[u]) return;

     top[son[u]] = top[u];

     dfs2(son[u]);

     for(int i = head[u]; i; i = e[i].nxt) {

         int nt = e[i].to;

         if(nt == f[u] || nt == son[u]) continue;

         top[nt] = nt;

         dfs2(nt);

     }

 }

 void update(int nd) {

     sum[nd] = sum[lson] + sum[rson];

 }

 void build(int l, int r, int nd) {

     if(l == r) { sum[nd] = A[l]; return;}

     int mid = (l + r) >> ;

     build(l, mid, lson);

     build(mid + , r, rson);

     update(nd);

 }

 int trie_sum(int L, int R, int l, int r, int nd) {

     if(L <= l && r <= R) return sum[nd];

     int tmp = , mid = (l + r) >> ;

     if(L <= mid) tmp += trie_sum(L, R, l, mid, lson);

     if(mid < R) tmp += trie_sum(L, R, mid + , r, rson);

     return tmp;

 }

 void sw(int &x, int &y) {

     x ^= y, y ^= x, x ^= y;

 }

 int query(int x, int y) {

     int ans = , tmp;

     for(; top[x] != top[y];) {

         if(dep[top[x]] < dep[top[y]]) swap(x, y);

         tmp = trie_sum(id[top[x]], id[x], , n, );

         ans += tmp;

         x = f[top[x]];

     }

     if(dep[x] < dep[y]) swap(x, y);

     tmp = trie_sum(id[y], id[x], , n, );

     ans += tmp - a[y];

     return ans;

 }

 int main()

 {

     n = rd; q = rd;

     for(int i = ; i < n; ++i) {

         int x = rd, y = rd, z = rd;

         add(x, y, z);

     }

     dfs1(); dfs2();

     build(, n, );

     for(; q; q--) {

         int x = rd, y = rd;

         printf("%d\n", query(x, y));

     }

 }