Определить количество ключевых слов "While", "FOR", "Input" - QBasic

CLS
DIM S(14) AS STRING
 
REM  +++ ИНИЦИАЛИЗАЦИЯ МАССИВА +++
 
S(1) = "z = 1073741824"
S(2) = "CLS"
S(3) = "INPUT" + " x = " + "x"
S(4) = "y = x"
S(5) = "x = ABS(x)"
S(6) = "FOR i = 1 TO 100"
S(7) = "   x = x + 1"
S(8) = "NEXT i"
S(9) = "DO WHILE z >= 1"
S(10) = "   IF x >= z THEN x = x - z"
S(11) = "   z = z / 2"
S(12) = "LOOP"
S(13) = "IF y < 0 THEN x = y + x - 1 ELSE x = y - x"
S(14) = "PRINT " + "[x] =" + "; x"
 
REM +++++++++++++++++++++++++++++++
 
k1 = 0
k2 = 0
k3 = 0
 
FOR i = 1 TO 14
   k = 1
   DO
      k = INSTR(k, S(i), "WHILE")
      IF k > 0 THEN
         k1 = k1 + 1
         k = k + 5
      END IF
   LOOP UNTIL k = 0
NEXT i
 
FOR i = 1 TO 14
   k = 1
   DO
      k = INSTR(k, S(i), "FOR")
      IF k > 0 THEN
         k2 = k2 + 1
         k = k + 3
      END IF
   LOOP UNTIL k = 0
NEXT i
 
FOR i = 1 TO 14
   k = 1
   DO
      k = INSTR(k, S(i), "INPUT")
      IF k > 0 THEN
         k3 = k3 + 1
         k = k + 5
      END IF
   LOOP UNTIL k = 0
NEXT i
 
PRINT "WHILE ="; k1
PRINT "FOR ="; k2
PRINT "INPUT ="; k3
END