#include<stdio.h>
#include<assert.h>
#include<math.h>
#include<string.h>

int stack[100];
int top = 0;

void push(int v){
    stack[top++] = v;
}

int pop(){
    return stack[--top];
}

int getInt(char *s){
    int i
    int ret=0;
    int size = strlen(s);
    
    for(i=0;i<size;i++){
        ret += (s[i]-'0')*pow(10,size-i-1);
    }
    return ret;
}

int main(){
    
    char s[1000];
    while(scanf("%s",s)!=EOF){
        if('0' <= s[0] && s[0] <= '9'){
          int v = getInt(s);
          push(v);
          continue;
            
        }
        
        int a,b;
        b = pop();
        a = pop();
        
        if(s[0] == '+'){
            push(a+b);
        }
        else if(s[0] == '-'){
            push(a-b);
        }
        else if(s[0] == '*'){
            push(a*b);
        }
        else{
            assert(0);
        }
    }
        
        printf("%d\n",pop());
        return 0;
        
}

