#include <iostream>

#include <cstdio>

#include <cstring>

#include <queue>

#include <algorithm>

using namespace std;

const int maxn = 100010;

const int maxe = 100010;

const int INF = 0x3f3f3f3f;

int n, m, Q;

struct edge {

    int t, d;

    edge* next;

}e[maxe * 2], *head[maxn]; int ne = 0;

void addedge(int f, int t, int d) {

    e[ne].t = t, e[ne].d = d, e[ne].next = head[f], head[f] = e + ne ++;

}

struct pr {

    int dis, pos;

    pr(int a, int b) {

        dis = a, pos = b;

    }

};

bool operator < (const pr &a, const pr &b) {

    return a.dis > b.dis;

}

priority_queue <pr> q;

int dis[maxn];

void dijkstra(int s) {

    memset(dis, INF, sizeof(dis));

    dis[s] = 0;

    for(int i = 1; i <= n; ++ i) q.push(pr(dis[i], i));

    while(!q.empty()) {

        pr x = q.top(); q.pop();

        if(x.dis != dis[x.pos]) continue;

        for(edge* p = head[x. pos]; p; p = p-> next) {

            if(dis[p-> t] > dis[x. pos] + p-> d)

                dis[p-> t] = dis[x. pos] + p-> d, q.push(pr(dis[p-> t], p-> t));

        }

    }

}

int int_get() {

    int x = 0; char c = (char)getchar(); bool f = 0;

    while(!isdigit(c)) {

        if(c == '-') f = 1;

        c = (char)getchar();

    }

    while(isdigit(c)) {

        x = x * 10 + (int)(c - '0');

        c = (char)getchar();

    }

    if(f) x = -x;

    return x;

}

void read() {

    n = int_get(), m = int_get(); Q = int_get();

    for(int i = 1; i <= m; ++ i) {

        int u, v, w;

        u = int_get(), v = int_get(), w = int_get();

        addedge(u, v, w); addedge(v, u, w);

    }

}

void sov() {

    dijkstra(1) ;

    while(Q --) {

        int a, b;

        a = int_get(), b = int_get();

        printf("%d\n", dis[a] + dis[b]);

    }

}

int main() {

    //freopen("test.in", "r", stdin);

    read(), sov();

    return 0;

}