Black Widow Rings

problem statement is here

#include<stdio.h>
int main(){
long int max,t,n,ar[10000],br[10000],i,j,p,m;
scanf("%ld",&t);
while(t--){
max=0;m=0;
scanf("%ld",&n);
for(i=0;i<n;i++){
scanf("%ld %ld",&ar[i],&br[i]);
if(ar[i]>max){
max=ar[i];
p=i;
}
}
br[p]=0;
for(i=0;i<n;i++){
if(m<br[i]){
m=br[i];
}
}
if(max>m){
printf("%ld\n",p+1);
}else{
printf("-1\n");
}
}
return 0;
}