//find two max and sum
if(a>b){
  if(b>c){
    //a>b>c => sum a+b
  }else{
    //a>b and c>b => sum a+c
  }
}else{
  if(a>c){
    //b>=a>c => sum a+b
  }else{
    //c>b>=a => sum c+b
  }
}

//find smallest, and sum the others
s0=0 //introduce another 2-bit variable called s
s1=0 //it essentially keeps the sign of the addition between the comparisons
if(a>b){
  s0=1
}
if(b>c){
  s1=1
}

//s = 00 then a<=b and b<=c, a is smallest
//s = 01 then a>b and b<=c, b is smallest
//s = 10 then a>b and b>c, c is smallest

if s = 00, sum c+b
if s = 01, sum c+a
if s = 10, sum a+b

//as you can see in the 3 if statements above
//whenever s has a 1 somewhere, then a should be added
//whenever s0 is 0 then b should be added
//whenever s1 is 0 then c should be added