/**
* Calculates the type of triangle
* 0 = not a triangle
* 1 = equilateral
* 2 = isoceles
* 3 = scalene
*/
function classifyTriangle(s1, s2, s3) {
    if (isNaN(s1) || isNaN(s2) || isNaN(s3)) {

        return 0;   
             
    } else if (s1 < 0 || s2 < 0 || s3 < 0) {
        
        return 0;

    } else if (s1 == 0) {
            
        return 0;

    } else if (s2 == 0) {
            
        return 0;

    } else if (s3 == 0) {
            
        return 0;

    } else if (s1 - s2 == s3) {
            
        return 0;

    } else if (s2 - s1 == s3) {
            
        return 0;

    } else if (s3 - s2 == s1) {
            
        return 0;

    } else if (s1 - s2 > s3) {
            
        return 0;

    } else if (s2 - s1 > s3) {
            
        return 0;

    } else if (s3 - s2 > s1) {
            
        return 0;

    } else if (s1 == s2 && s1 == s3 && s2 == s3) {
            
        return 1;

    } else if (s1 != s2 && s1 != s3 && s2 != s3) {
            
        return 3;
        
    } else {
            
        return 2;
    }
}