#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>

#define MAX_SIZE 5200
#define MAX_NODE 501

typedef struct {
    int start;
    int end;
    int time;
} Edge;

int main() {
    int T;
    scanf("%d", &T);

    Edge* edge = (Edge*)malloc(sizeof(Edge)*MAX_SIZE);
    int* distance = (int*)malloc(sizeof(int)*MAX_NODE);

    while(T--) {
        int N, M, W;
        scanf("%d %d %d",&N, &M, &W);
        
        // ROAD
        for(int i=0; i<2*M; i+=2) {
            int S, E, T;
            scanf("%d %d %d",&S, &E, &T);

            Edge temp1 = {S, E, T};
            Edge temp2 = {E, S, T};

            edge[i] = temp1;
            edge[i+1] = temp2;
        }

        // WORM HOLE
        for(int i=0; i<W; i++) {
            int S, E, T;
            scanf("%d %d %d",&S, &E, &T);

            Edge temp = {S, E, T*(-1)};

            edge[2*M+i] = temp;
        }

        memset(distance, 0, sizeof(int)*MAX_NODE);
        bool negative_cycle = false;

        for(int n=0; n<N; n++) {
            for(int i=0; i<2*M+W; i++) {
                int s = edge[i].start;
                int e = edge[i].end;
                int t = edge[i].time;

                if(distance[e] > distance[s] + t) {
                    distance[e] = distance[s] + t;

                    if(n==N-1) {
                        negative_cycle = true;
                        break;
                    }
                }
            }
        }
        
        printf("%s\n", negative_cycle ? "YES" : "NO");
    }

    free(edge);
    free(distance);
    return 0;
}