#include <stdio.h> 
/* Define the trade structure */
struct trade {double price; int number;};
/* Define trade_price */
double trade_price (struct trade t) {
  return t.price * t.number;
}
/* Define trade array */
struct trade trades[100];
main ( ) {
  /* Declare various variables */
  int limit, counter, number;
  double price, sum = 0.0;
  /* Read numbers and stuff them into array */
  for (limit = 0; 2 == scanf ("%lf%i", &price, &number); ++limit) {
    trades[limit].price = price;
    trades[limit].number = number;
  }
  /* Add all products */
  for (counter = 0; counter < limit; ++counter)
    sum = sum + trade_price(trades[counter]);
  printf ("The total value of the %i trades is %f.\n",
                                  limit,       sum);
}