#include<iostream>
#include<cstring>
using namespace std;
char stack[1000010];
long long len_s, num[1000010], top;
int main() {
	cin >> stack;
	len_s = strlen(stack);
	for (int i = 0; i < len_s; i++) {
		if (stack[i] == '@') break;
		if (stack[i] == '.') continue;
		if (stack[i] - '0' >= 0 && stack[i] - '0' <= 9) {
			if (i - 1 >= 0) {
				if (stack[i - 1] != '.' && stack[i - 1] != '+' && stack[i - 1] != '-' && stack[i - 1] != '*' && stack[i - 1] != '/' && stack[i - 1] != '%') {
					num[top] = num[top] * 10 + (stack[i] - '0');
				}
				else {
					num[++top] = stack[i] - '0';
				}
			}
			else {
				num[++top] = stack[i] - '0';
			}
		}
		else {
			switch (stack[i]) {
				case '+':
					num[--top] = num[top] + num[top + 1];
					break;
				case '-':
					num[--top] = num[top] - num[top + 1];
					break;
				case '*':
					num[--top] = num[top] * num[top + 1];
					break;
				case '/':
					num[--top] = num[top] / num[top + 1];
					break;
				case '%':
					num[--top] = num[top] % num[top + 1];
					break;
			}
		}
	}
	cout << num[1] << endl;
	return 0;
}