To decide whether a number of n digits is divisible by 7, we can define a process by which its magnitude is reduced as follows: (i1 , i2 , i3…..in are the digits of the number, starting from the most significant digit). i1 i2…in fi i1 . 3 n–1 + i2, 3 n–2 + …. + In3 0 . e.g. 259 fi 2.3 2 + 5.3 1 + 9.3 0 = 18 + 15 + 9 = 42 Ultimately the resulting number will be seven after repeating the above process a certain number of times. After how many such stages, does the number 203 reduce to 7?

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