#include <iostream>
#include <stack>
#include <string>

int operatorLevel(char op) {
    switch (op) {
        case '+': case '-': return 1;
        case '*': case '/': return 2;
        default: return 0;
    }
}
bool isOp(char c) {
    return c == '+' || c == '-' || c == '*' || c == '/';
}



std::string convertToPostfix(const std::string& infix) {
    std::stack<char> opStack;
    std::string postfix;

    for (char c : infix) {
        if (isalnum(c)) {
            postfix += c;
        } else if (c == '(') {
            opStack.push(c);
        } else if (c == ')') {
            while (!opStack.empty() && opStack.top() != '(') {
                postfix += opStack.top();
                opStack.pop();
            }
            opStack.pop();
        } else if (isOp(c)) {
            while (!opStack.empty() && operatorLevel(c) <= operatorLevel(opStack.top())) {
                postfix += opStack.top();
                opStack.pop();
            }
            opStack.push(c);
        }
    }
    while (!opStack.empty()) {
        postfix += opStack.top();
        opStack.pop();
    }
   return postfix;
}





int main() {
    std::string infixExpression;
    std::cout << "Enter an infix expression: ";
    std::cin >> infixExpression;
    std::string postfixExpression = convertToPostfix(infixExpression);
    std::cout << "The postfix expression is: " << postfixExpression << std::endl;
    return 0;
}