// poj3615

#include<algorithm>

#include<iostream>

#include<cstdlib>

#include<cstring>

#include<cstdio>

#include<cmath>

#define LL long long

#define inf 2147483640

#define Pi acos(-1.0)

#define free(a) freopen(a".in","r",stdin),freopen(a".out","w",stdout);

using namespace std;

inline LL getint() {

	int f,x=0;char ch=getchar();

	while (ch<='0' || ch>'9') {if (ch=='-') f=-1;else f=1;ch=getchar();}

	while (ch>='0' && ch<='9') {x=x*10+ch-'0';ch=getchar();}

	return x*f;

}

const int maxn=310;

int f[maxn][maxn],n,m,T;

int main() {

	scanf("%d%d%d",&n,&m,&T);

	for (int i=1;i<=n;i++)

		for (int j=1;j<=n;j++) if (i!=j) f[i][j]=inf;

	for (int u,v,w,i=1;i<=m;i++) {

		scanf("%d%d%d",&u,&v,&w);

		f[u][v]=w;

	}

	for (int k=1;k<=n;k++)

		for (int i=1;i<=n;i++)

			for (int j=1;j<=n;j++)

				f[i][j]=min(f[i][j],max(f[i][k],f[k][j]));

	for (int x,y,i=1;i<=T;i++) {

		scanf("%d%d",&x,&y);

		if (f[x][y]==inf) puts("-1");

		else printf("%d\n",f[x][y]);

	}

	return 0;

}