This is not a trick question. But don't be scared...

My school is offering 5 school trips for my year group this year. Students go on the trips as follows: 121 visit Germany. 162 visit France. 71 visit South Africa. 120 visit London. 150 visit the local museum. 106 visit Germany and France. 111 visit Germany and South Africa. 72 visit Germany and London. 60 visit Germany and the local museum. 55 visit France and South Africa. 45 visit France and London. 40 visit France and the local museum. 30 visit South Africa and London. 36 visit South Africa and the local museum. 30 visit London and the local museum. 25 visit Germany, France, and South Africa. 25 visit Germany, France, and London. 25 visit Germany, France, and the local museum. 25 visit Germany, South Africa, and London. 25 visit Germany, South Africa, and the local museum. 25 visit Germany, London, and the local museum. 25 visit France, South Africa, and London. 25 visit France, South Africa, and the local museum. 25 visit France, London, and the local museum. 25 visit South Africa, London, and the local museum. 10 visit Germany, France, South Africa, and London. 7 visit Germany, France, South Africa, and the local museum. 7 visit Germany, France, London, and the local museum. 5 visit Germany, South Africa, London, and the local museum. 5 visit France, South Africa, London, and the local museum. 3 visit all five. 35 don't go on any trips. How many people are in my year group?

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