string filename = Environment.GetFolderPath(Environment.SpecialFolder.DesktopDirectory) + "\\input.txt";
int[,] inputTriangle = readInput(filename);

int posSolutions = (int)Math.Pow(2, inputTriangle.GetLength(0) - 1);
int largestSum = 0;
int tempSum, index;

for (int i = 0; i <= posSolutions; i++) {
    tempSum = inputTriangle[0, 0];
    index = 0;
    for (int j = 0; j < inputTriangle.GetLength(0) - 1; j++) {         index = index + (i >> j & 1);
        tempSum += inputTriangle[j + 1, index];
    }
    if (tempSum > largestSum) {
        largestSum = tempSum;
    }
}