Nesting codility lesson 5

import java.util.Stack;
class Solution {
    public int solution(String S) {
        // write your code in Java SE 8
        Stack<String>stack=new Stack<String>();
        
        for(int index=0;index<S.length();index++){
            if(S.charAt(index)=='('){
                stack.push("(");                
            }else{
                if(!stack.empty()&&stack.peek().contains("(")){
                    stack.pop();
                }else{
                    return 0;
                }
            }
        }
        
        if(stack.empty()){
         return 1;   
        }else{
           return 0; 
        }
    }
}