Table:
0
A
B
C
D
E
1
Head of mission
Tenure begins
Tenure ends
French Head of State
Japanese emperor
2
Jean Daridan
1959
1961
Charles de Gaulle
Hirohito
3
Étienne Dennery
1961
1964
Charles de Gaulle
Hirohito
4
François Missoffe
1964
1966
Charles de Gaulle
Hirohito
5
Louis de Guiringaud
1966
1972
Georges Pompidou
Hirohito
6
François Lefebvre de Laboulaye
1972
1975
Valéry Giscard d'Estaing
Hirohito
7
Jean-Pierre Brunet
1975
1977
Valéry Giscard d'Estaing
Hirohito
8
Louis Dauge
1977
1979
Valéry Giscard d'Estaing
Hirohito
9
Xavier Daufresne de la Chevalerie
1979
1982
François Mitterrand
Hirohito
10
André Ross
1982
1985
François Mitterrand
Hirohito
11
Gilbert Pérol
1985
1987
François Mitterrand
Hirohito
12
Bernard Dorin
1987
1991
François Mitterrand
Akihito
13
Loïc Hennekinne
1991
1993
François Mitterrand
Akihito
14
Jean-Bernard Ouvrieu
1993
1998
Jacques Chirac
Akihito
15
Maurice Gourdault-Montagne
1998
2002
Jacques Chirac
Akihito
16
Bernard Faubournet de Montferrand
2002
2006
Jacques Chirac
Akihito
17
Gildas Le Lidec
2006
2007
Jacques Chirac
Akihito

Questions and formulas:
Question: How many French heads of state have a head of mission of Xavier Daufresne de la Chevalerie?
Formula: ROWS(UNIQUE(FILTER(D1, A1="Xavier Daufresne de la Chevalerie")))
Formula2: ROWS(UNIQUE(FILTER(D2:D17, A2:A17="Xavier Daufresne de la Chevalerie")))
Level: medium