#include <stdio.h>#include <cstring>#include <iostream>#include <algorithm>using namespace std;int N, M, K;int p[5001];long long sum[5001];int find(int x){ if(p[x] == -1) return x; int f = find(p[x]); sum[x] = sum[x] + sum[p[x]]; p[x] = f; return f;}int main(){ while(~scanf("%d%d%d", &N, &M, &K)) { for(int i = 0; i <= N; ++i) { sum[i] = 0; } memset(p, -1, sizeof(p)); for(int i = 1; i <= M; ++i) { int a, b; long long w; scanf("%d%d%lld", &a, &b, &w); --a; int fa = find(a); int fb = find(b); if(fa < fb) { p[fb] = fa; sum[fb] = sum[a] + w - sum[b]; } if(fa > fb) { p[fa] = fb; sum[fa] = sum[b] - w - sum[a]; } } for(int i = 1; i <= K; ++i) { int a, b; scanf("%d%d", &a, &b); --a; int fa = find(a), fb = find(b); if(fa != fb) puts("UNKNOWN"); else printf("%lldn", sum[b] - sum[a]); } puts(""); } return 0;}
