long i,t,a,b,c;g(long p,long q){return q?g(q,p%q):p;}main(s){scanf("%d%d%d",&a,&b,&c);s=abs(g(b*(a-c),a*(b-c)));i=!printf("%ld/%d",i/t,s/(t=g(i=a*b*c,s)));}