Bicyclic compound

A compound represented by the formula:

• wherein
• ring P is an optionally further substituted, optionally crosslinked 4- to 8-membered ring;
• ring Q is an optionally further substituted 5- or 6-membered ring;
• ring R is an optionally further substituted 5- or 6-membered ring;
• ring S is an optionally further substituted 4- to 7-membered ring;
• X is —O—, —C(R3)(R4)— or —N(R5)—;
• R1 is an amino group optionally mono- or di-substituted by an optionally substituted C1-6 alkyl group, a C1-6 alkyl group optionally substituted by a halogen atom, an optionally substituted C3-6 cycloalkyl group or an optionally substituted C1-6 alkoxy group;
• R2 is a C1-6 alkyl group optionally substituted by a halogen atom or an optionally substituted C3-6 cycloalkyl group;
• R3, R4 and R5 are the same or different and each is a hydrogen atom or a substituent;
• m and n are the same or different and each is 1 or 2, and m+n is 2 or 3,
• or a salt thereof.