using System;
class Program
{
static int replace_digit_in_number(int number, int d1, int d2) {
int result = 0, multiply = 1;
while (number != 0) {
int reminder = number % 10;
if (reminder == d1)
result += d2 * multiply;
else
result += reminder * multiply;
multiply *= 10;
number = number / 10;
}
return result;
}
static void Main()
{
int number = 18803808;
Console.WriteLine(replace_digit_in_number(number, 8, 7));
}
}
/*
run:
17703707
*/