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


int main(){
????int cal[100], top = 0;
????char s[1000000];

????while(1){

????????if(scanf("%s",&s) == EOF) break; 

????????if(s[0] == '+'){
????????????cal[top-1] = cal[top-1] + cal[top];
????????????top--;
????????}
??
????????else if(s[0] == '-'){
????????????cal[top-1] = cal[top-1] - cal[top];
????????????top--;
????????}

????????else if(s[0] == '*'){
????????????cal[top-1] = cal[top-1] * cal[top];
????????????top--;
????????}

????????else cal[++top] = atoi(s);
????}
????????
????printf("%d\n",cal[top]);
????
????return 0;
}