I have created some program for this.But printed a,b,c values are not correct.Please check this whether it is correct or not?

n=input("Enter the no.of McNuggets:")   
a,b,c=0,0,0   
count=0   
for a in range(n):  
    if 6*a+9*b+20*c==n:     
            count=count+1
               break
    else:  
        for b in range(n):  
            if 6*a+9*b+20*c==n:  
                count=count+1  
                break  
            else:  
                for c in range(n):  
                    if 6*a+9*b+20*c==n:  
                        count=count+1  
                        break  
if count>0:  
    print "It is possible to buy exactly",n,"packs of McNuggetss",a,b,c  
else:  
    print "It is not possible to buy"