var leftMost = -1;

for (var i = 0 ; i < binaryMatrix.length ; i++) {
    if (binaryMatrix[i][binaryMatrix[0].length-1] == 0){
        continue;   
    } else if (leftMost == -1) {
        leftMost = binaryMatrix[0].length-1;   
    }

    if (binaryMatrix[i][leftMost] == 0) {
        continue;   
    } else {
        while (leftMost-1 >= 0 && binaryMatrix[i][leftMost-1] == 1) {
            leftMost--;   
        }
        if (leftMost == 0) {
            break;   
        }
    }
}
return leftMost;