x, y-numere
x, y>99 si x, y<1000
x:4=c rest r1, r1∈{0, 1, 2, 3}, x=4c+r1
y:4=c rest r2, r2∈{0, 1, 2, 3}, y=4c+r2
daca c=25 x=100+r1
y=100+r2, nr pot fi 100 si 101, 101 si 102, 102 si 103, sau oricare combinatii din 100,101, 102 si 103
daca c=249 x=996+r1
y=996+r2, x si y ∈{996, 997, 998, 999}
deci c∈[25, 249]
