var summa = document.getElementById("summa");
		summa.onkeypress = NumbersOnly;
		var period = document.getElementById("period");
		period.onkeypress = NumbersOnly;		
		
		function NumbersOnly(e) {
			if(this.id=="summa")
				var dec=true;
			var key;
			var keychar;

			if (window.event)
				key = window.event.keyCode;
			else 
				if (e)key = e.which;
			else 
				return true;	
			keychar = String.fromCharCode(key);

			if ((key==null) || (key==0) || (key==8) || (key==9) || (key==13) || (key==27) )
				return true;
			else if ((("0123456789").indexOf(keychar) > -1))
				return true;
			else if (dec && (keychar == "." || keychar == ",") && this.value.indexOf(".") == -1 && this.value.indexOf(",") == -1) {
				return true;
			} else
				return false;
		}
	
		var button = document.getElementById("calculate");
		button.onclick = function(event) {
			var a = parseFloat(document.getElementById('summa').value.replace(",","."),10);
			var b = parseInt(document.getElementById('period').value,10);
                        var c = Calculate(a,b).toFixed(0);
			document.getElementById("result").value = c;
                        document.getElementById("percent").value = c*100/a;
		}
		
		function Parameters(_c_min,_c_max,_d,_e,_f,_g) {
			this.c_min = _c_min;
			this.c_max = _c_max;
			this.d = _d;
			this.e = _e;
			this.f = _f;
			this.g = _g;
		}

		var arrParameters = [
			new Parameters(0,10,50,0.014,0.058,0.042),
			new Parameters(11,20,50,0.043,0.173,0.042),
			new Parameters(21,30,50,0.074,0.298,0.042),
			new Parameters(31,40,50,0.103,0.413,0.044),
			new Parameters(41,50,50,0.132,0.528,0.044),
			new Parameters(51,60,50,0.163,0.653,0.044),
			new Parameters(61,70,50,0.192,0.768,0.045),
			new Parameters(71,80,50,0.221,0.883,0.045),
			new Parameters(81,90,50,0.252,1.008,0.045),
			new Parameters(91,100,50,0.281,1.123,0.047),
			new Parameters(101,110,50,0.310,1.238,0.047),
			new Parameters(110,4294967295,50,0.341,1.363,0.047),
		];
	
	 
		function Find(b){
			 for (var k in arrParameters) {
				if(arrParameters[k].c_min <= b && arrParameters[k].c_max >= b)
					return arrParameters[k];
			}
		}
		
		function Calculate(a,b){
			var param = Find(b);
			return a*(param.e+param.f+param.g*b*0.9)/100+param.d;
			
		}