Code:
TTEuclide[a_, b_] := If[a == b,
Return[a]
,
If[a > b,
Return[TTEuclide[a - b, b]];
,
Return[TTEuclide[a, b - a]];
];
];
Clear[a, b];
a = Input["Nhap gia tri a"];
b = Input["Nhap gia tri b"];
Print["UCLN(a,b) = ", TTEuclide[a, b]];