n=int(int(input("Enter n: ")))
d={}
for i in range(n):
roll_no=int(input("Enter roll no: "))
name=input("Enter name: ")
marks=int(input("Enter marks: "))
d[roll_no]=[name,marks]
for k in d:
if(d[k][1]>75):
print(d[k][0])

Output:

Enter n: 2

Enter roll no: 1

Enter name: a

Enter marks: 85

Enter roll no: 2

Enter name: b

Enter marks: 55

a