We are given two triangles with angles \( P, Q, R, S \), and other conditions.
- From condition I: \( A + B = 90^\circ \), this means the angles \( A \) and \( B \) in the first triangle add up to 90 degrees. This implies that the remaining two angles in the first triangle must also add up to 90 degrees.
- From condition II: \( P + Q = R + S \), this equation means that the sum of angles \( P \) and \( Q \) is equal to the sum of angles \( R \) and \( S \).
In any triangle, the sum of the interior angles is always \( 180^\circ \). Therefore, in each triangle, the sum of the angles must be \( 180^\circ \). Thus:
\[
P + Q + R + S = 180^\circ + 180^\circ = 360^\circ
\]
Therefore, the value of \( P + Q + R + S \) is \( 360^\circ \).
Thus, the correct answer is \( \boxed{1} \).