#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<math.h>
#define N 13
#define pi M_PI
int top=0;
char s[200];
int S[101];

void push(int x){
    top++;
    S[top]=x;
}
int pop(){
    top--;
    return S[top+1];
}
int main(){
    int a,b;
    int result;
    while(scanf("%s",s)!=EOF){
        if(s[0]=='+'){
            push(pop()+pop());
        }else if(s[0]=='-'){
            a=pop();
            b=pop();
            push(b-a);
        }else if(s[0]=='*'){
            push(pop()*pop());
        }else if(s[0]=='/'){
            a=pop();
            b=pop();
            push(b/a);
        }else{
            push(atoi(s));
        }
    }
    printf("%d\n",pop());
    return 0;

}
