import std.stdio;
import std.string;
import std.conv;
import std.bigint;
import std.container.slist;

string[] lex(string s){
  string[] result;
  long i = 0;
  while(i < s.length){
    switch(s[i]){
      case '+', '-', '*', '(', ')':
        result ~= s[i .. i + 1];
        i++;
        break;
      default:
        auto j = i;
        while(i < s.length && s[i] >= '0' && s[i] <= '9'){
          i++;
        }
        result ~= s[j .. i];
    }
  }
  return result;
}

int[string] priority = ["+" : 2, "-" : 2, "*" : 1, "(" : 3];

string[] rpn(string[] l){
  string[] result;
  auto stack = SList!string();
  auto minus = false;
  foreach(i, s; l){
    auto p = priority.get(s, 0);
    switch(s){
      case ")":
        while(!stack.empty && stack.front != "("){
          result ~= stack.front;
          stack.removeFront;
        }
        stack.removeFront;
        break;
      case "(":
        stack.insert(s);
        break;
      case "-":
        if(stack.empty || l[i - 1] in priority){
          minus = !minus;
          break;
        }
        goto default;
      default:
        while(!stack.empty && p >= priority.get(stack.front, 0)){
          result ~= stack.front;
          stack.removeFront;
        }
        if(minus){
          s = "-" ~ s;
        }
        minus = false;
        stack.insert(s);
    }
  }
  while(!stack.empty){
    result ~= stack.front;
    stack.removeFront;
  }
  return result;
}

BigInt eval(string[] l){
  auto stack = SList!BigInt();
  foreach(s; l){
    switch(s){
      case "+":
        auto a = stack.front;
        stack.removeFront;
        stack.front += a;
        break;
      case "-":
        auto a = stack.front;
        stack.removeFront;
        stack.front -= a;
        break;
      case "*":
        auto a = stack.front;
        stack.removeFront;
        stack.front *= a;
        break;
      default:
        stack.insert(BigInt(s));
    }
  }
  return stack.front;
}

void main(){
  auto N = readln.chomp.to!long;
  auto S = readln.chomp;
  writeln(S.lex.rpn.eval);
}