#include<stdio.h>
#include<stdlib.h>
int S[1001];
inline void fail(void){ puts("0"); exit(0); }
inline void succ(void){ puts("1"); exit(0); }
int main(int argc, char *argv[])
{
    int n, i, d, ans = 0;
    FILE *in, *res;
    in = fopen(argv[1],"r");
    res = fopen(argv[2],"r");
    fscanf(in, "%d", &n);
    for( i = 0 ; i < n ; i++ )
        fscanf(in, "%d", &S[i]);
    for( i = 0 ; i < n ; i++ )
        if( S[i] ) ans++;
    fscanf(res, "%d", &d);
    if( ans < 2 )
    {
        if( d == -1 ) succ();
        else fail();
    }
    else if( ans == 2 )
    {
        if( d == 0 ) succ();
        else fail();
    }
    if( d > 1000000 ) fail();
    while(d--)
    {
        int a, b;
        fscanf(res, "%d%d",&a,&b);
        if( S[a-1] > S[b-1] ) fail();
        S[b-1]-=S[a-1];
        S[a-1]*=2;
    }
    for( i = ans = 0 ; i < n ; i++ )
        if( S[i] ) ans++;
    if( ans == 2 ) succ();
    else fail();
}