This is my first post, hope someone can help me.

I have inherited an excel sheet that tracks the activities on site, by date and personnel. It looks something like this.

Date | Site | Person |

21/4/2015 | 1 | A, B, C |

21/4/2015 | 2 | D, E |

22/4/2015 | 2 | A, B, C |

22/4/2015 | 3 | D, E, F |

22/4/2015 | 4 | A, C, F |

22/4/2015 | 5 | B, E, F |

23/4/2015 | 5 | A, B |

23/4/2015 | 6 | A |

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I have to do the report how many days each person spend on sites (out of office).

Based on the table above this would be the result:

Person | Days |

A | 3 |

B | 3 |

C | 2 |

D | 2 |

E | 2 |

F | 1 |

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I've tried with COUNTIF, but simple COUNTIF function would not help as I need to count each person only once per given date. For example person A appears 5 times in total, but only on 3 different days. Or Person F appears 3 times, but only on 1 day so it was 1 day out of office.

So I'm stuck now.

One more thing, I can't change the appearance of original excel sheet.

Could anyone suggest how to make a formula that would automatically count this?