exception of " Index was outside the bounds of the array."

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication10
{
    delegate int MathFunction(int int1, int int2);
    class Program
    {

        static int Add(int int1, int int2)
        {
            return int1 + int2;
        }

        static int Subtract(int int1, int int2)
        {
            return int1 - int2;
        }

        static int Multiply(int int1, int int2)
        {
            return int1 * int2;
        }

        static int Divide(int int1, int int2)
        {
            return int1 / int2;
        }

        static void PrintResult(MathFunction mathFunction, int int1, int int2)
        {
            int result = mathFunction(int1, int2);
            Console.WriteLine(String.Format("Result is {0}", result));
        }
        static void Main(string[] args)
        {
             <big>int left = Convert.ToInt32(args[0]);</big>  //here i am getting exception
            char theOperator = args[1][0];
            int right = int.Parse(args[2]);
            MathFunction mathFunction;
            if (theOperator == '+')
                mathFunction = Add;
            else if (theOperator == '-')
                mathFunction = Subtract;
            else if (theOperator == '*')
                mathFunction = Multiply;
            else
                mathFunction = Divide;
            PrintResult(mathFunction, left, right);
        }
   
    }
}