#include<stdio.h>
#include<stdlib.h>
#include<string.h>
int top ,S[1000];
void push(int x){
S[++top] = x;
}
int pop(){
top--;
return S[top+1];
}
int main(){
int a,b;
top = 0;
char s[100];
printf("输入");
while(scanf("%s",s) !=EOF){
if( s[0]=='+') {
a = pop();
b = pop() ;
push(a + b);
} else if (s[0] =='-'){
a = pop();
b = pop() ;
push(a - b);
} else if(s[0] =='*'){
a = pop() ;
b = pop() ;
push(a * b);
}else {
push(atoi(s));
}
}
printf("%d/n",pop());
return 0;
}