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



long evaluate_rpn(int count, char *tokens[]) {
    // TODO: implement this function
    (void) count;
    (void) tokens;
    return 0;
}


int main(void) {
    static char storage[1000][50];
    char *tokens[1000];
    int count = 0;
    while (count < 1000 && scanf("%49s", storage[count]) == 1) {
        tokens[count] = storage[count];
        count++;
    }
    printf("%ld\n", evaluate_rpn(count, tokens));
    return 0;
}