QBASIC PROGRAM TO CHECK STRONG NUMBER

CLS
DIM N AS INTEGER,NUM AS INTEGER,D AS INTEGER,S AS INTEGER

INPUT"ENTER ANY NUMBER";N
NUM=N
F=1
WHILE N>0
D=N MOD 10
    WHILE D>0
      F=F*D
      D=D-1
    WEND
S=S+F
F=1
N=N\10
WEND

IF S=NUM THEN
    PRINT"STRONG NUMBER"
ELSE
    PRINT"NOT STRONG NUMBER"
END IF

END