#include <iostream>#include <cstdio>#include <cmath>#include <cstring>#include <algorithm>#include <queue>#include <stack>#include <vector>#include <cstdlib>#include <string>using namespace std;int n,m;int f[210];struct node{    int u,v;    int w;}map[1020];int getf(int a){    if(f[a] == a)        return a;    f[a] = getf(f[a]);    return f[a];}void merge(int a, int b){    int x = getf(a);    int y = getf(b);        if(x!=y)        f[y] = x;}void init(){    for(int i=1; i<=n; i++)    {        f[i] = i;    }}bool cmp(node a, node b){    return a.w < b.w;}int solve(int start, int end){    int maxn = -1;    int minn = 999999999;    sort(map,map+m,cmp);    int res = 999999999;        for(int k = 0; k < m; k++)    {        init();        maxn = -1;        minn = 999999999;        for(int i = k; i < m; i++)        {            if(getf(map[i].u) != getf(map[i].v))            {                merge(map[i].u, map[i].v);                maxn = max(maxn, map[i].w);                minn = min(minn, map[i].w);             }            if(getf(start) == getf(end))            {                res = min(maxn - minn, res);                break;            }        }    }        if(res == 999999999)        res = -1;    return res;}int main(){    int q;    while(scanf("%d %d", &n, &m)!=EOF)    {        for(int i=0; i<m; i++)        {            scanf("%d %d %d", &map[i].u, &map[i].v, &map[i].w);        }                scanf("%d", &q);        int s[20][2];                for(int i=1; i<=q; i++)        {            init();            scanf("%d %d", &s[i][0], &s[i][1]);            printf("%d\n", solve(s[i][0],s[i][1]));                    }    }    return 0;}