#include<stdio.h>

long n, s, t;
long long suma;

void citire()
{
  long i, j, k;
  freopen("branza.in","r",stdin);
  scanf("%ld %ld %ld",&n, &s, &t);
  for (i=1; i<=n; i++)
    { scanf("%ld %ld",&k, &j);
      suma+=(k*j);
    }
  freopen("branza.out","w",stdout);
  printf("%lld",suma);
}

int main()
{
  citire();
  return 0;
}