a,b,c,d,e,f;main(){scanf("%d%d%d",&d,&e,&f);d>e?d^=e^=d^=e:0;e>f?f^=e^=f^=e:0;d>e?d^=e^=d^=e:0;!a&&(a=d+e,b=d+f,c=e+f)&&!main()||printf("%d",a*f+b*e+c*d<<1);exit(0);}